Prognostic Implications of Altered Human Epidermal Growth Factor Receptors (HERs) in Gastric Carcinomas: HER2 and HER3 Are Predictors of Poor Outcome

Abstract

Purpose The human epidermal growth factor receptor (HER) family consists of four members: ErbB-1 (HER1), ErbB-2 (HER2), ErbB-3 (HER3), and ErbB-4 (HER4). These receptors activate numerous downstream pathways in response to extracellular ligands, regulating diverse processes that include differentiation, migration, proliferation, and survival. Alterations in these genes play a role in the development and progression of many human cancers. In gastric carcinomas (GCs), expression of HER1 and HER2 is thought to be a prognostic factor and target of novel biologic agents. The effect of HER3 or HER4 expression in GC has not been sufficiently studied. In this study, we explored the gene and protein expression of the HER family in GC to establish new potential prognostic factors. Patients and Methods Immunohistochemistry and fluorescence in situ hybridization were performed in 221 patients with GC using tissue microarray. Correlation between the expression or amplification of HER genes and the clinicopathologic parameters was statistically analyzed. Results Alterations of members of the HER family were significantly associated with the parameters involved in tumor progression, including depth of tumor invasion, involved lymph nodes, and tumor stage. In addition, HER2 amplification and HER3 expression were significantly related to worse survival. Conclusion These results reveal that all members of the HER family are expressed in GC. Furthermore, expression of HER2 and HER3 is a significant predictor of poor survival in GC. Therefore, the development of HER-targeted agents and agents targeting downstream signaling pathways provides new possibilities in the treatment of GC.